Electrical compression resistance unit.



I-I\r\l 'Il l l n Patented Sept'. 19, v1916.

Inventor Attorneys lUD-H4 P. 1'. RAY. ELECTRICAL COMPRESSION RESISTANCE UNIT.

APPL'ICATION FILED DEC- 2. T915.

Witnesses man?" UI A .STATES 'mmmommmlPAUL J.. RAY, or LAKEwooD, oHIo.

ELECTRICAL coMrREssIoN RESISTANCE UNIT.

To all whom' z't may concern.' Y

Be it known that I, PAUL J. RAY, a citizen of the United States, residing at Lakewood in the county of Cuyahoga .and State o Ohio, have invented a new and useful Electrical Compression Resistance Unit, of

l which the following isa specification.

manner, as to enhance the utility of the unit, thereby attaining a greater permanence of resistance, a better operating perv:as

formance considering the various temperatures to which the resistance is subjected, a more desirable exactitude of the conditions desired when subjected to frequent operation, andl a more perfect restoration of the unit when released, to restore the initial resistance value without shaking or jarring the unit. 'l

With the foregoing and other objects in view which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter de- Arheovstat, the unit being broken away toscribed and claimed, it lbeing understood that changesin the precise embodiment of the invention herein disclosed can be made within the scope of what is claimed without de arting from the spirit .of the invention.

he invention is illustrated in the accompanying drawings, wherein j Figure 1 is a side elevation of the complete device constructed as a compression foreshorten the same..` Fig. 2 is an enlarged longitudinal sectional view through the resistance unit and radiator. F ig: 3 is a section taken on the line 3 3 of Fig. 2.

Referring to the drawing, the'numerall designates a support which constitutes with the clamp 2, composed of -two members, a proper bearing means for the resistance unit, which, as will presently appear is mounted in the sleeve 3 of insulation disposed within the clamp 2.

A metal tube 4 is lined with a tube 5 of insulatino' material and mounted Withinl said insu ating tube is a series or plurality .Specification of Letters Patent. Patented Sept, 19, 1916, Application led December 2' 1915. Serial No. 64,752.

of resistance disks or. members 6, the same being so constructed as to have their resistance increased as the compression thereupon -is released, and to have their resistance reduced as the same are compressed more closely together.

In one end of the insulating tube 5 is a metal disk 7 carrying the concentric stein 8 which projects through an insulating sleevev 9, several washers 10 of insulating material being .disposed within the tube 4 aboutA the sleeve 9 while several washers l1 of insulating material are disposed about the stem exteriorly of the metal tube 4, as clearly illustrated in Fig. 2. The outer end of the stem 8 is threaded to receive the terminal.

carrying nuts 12 to which -is connected the terminal wire or conductor 13. Mounted in the other end of the sleeve 5 is an insulating bushing 14 in which is mounted for sliding movement, the-stein 15 carrying the terminal conductor 17 and the button 16 of insulation. Upon the inner end of the stem 15 within the tube 5, as at 18, is attached a screw `19 which is connected to and carries the terminal disk 2O which'acts as a means for compressing the compression' disks 6 between it andl the disk 7. lA resilient compression transmitting member 21 abuts against the button 16 and is operated by the lever cam 22, the member 2l being so constructed as to normally hold the disks 6 in proper contact to prevent air gaps therebetween. j

Each conductor disk 6 is preferably made granular or powdered form or both com-` bined, or of any other by-productsof the process of manufacturing crystalline carborundum, carbrundum, suitable grade or corundum, or any other conductive crystallinel abrasive material, combined with an adhesive compound, such as silicate of soda which may afterward be har ene y applying Y ressure and heat to the said surface. The individual use of either crystalline carborundum or amorphous carborundum is of adof graphite or hard carbon, orf-any' other vantage to enhance the effectiveness of the unit, but when both forms of carborundum or equivalent material are combined, the ad- Contact surface better than conductor 'members heretofore produced. As the resistance is obtained by the imperfect contact between -the surfaces :of the disks, and as the disks are formed by sawing sectional-wise plates or disks from a .cylindrical piece of material, the saw marksin the surface of the disks are quite uniform and in instances where it -is necessary to parallel the surfaces of the disks by grinding them, the conditions of the ground surface are more uniform than the saWed surfaces. Thus after the disks have been subjected to the process stated herein,'the contact resistance-is practically uniform throughout the length of the resistance unit. "hen corundum is used, it is preferably admixed with some suitable conducting material, and is generally used when a high maximum resistance is required.

.The amorphous carborundum hereinrereferred to is commercially known as carbo *manufacturing carborundum which is made by heating in an electrical furnace, coke, sand, salt and sawdust. In the process of manufacturing carborundum the mixture of materials is heated in a high resistance furnace for about thirty-six hours` after which the reaction is completed, and there is left a core of graphite and surrounding the core is a layer of crystallized carborundum, about approximately sixteen inches thick and outside of this is a shell of amorphous carborundum -which contains a percentage of crystallized carborundum, the remaining materials being unchanged and being used for a new charge. The materials other than graphite, carborundum and the unchanged mechanical mixture in the foregoing process is known as carborundum re sand or amorphous carborundum, and either the carborundum fire sand or the crystalline carborundum are used separately or mixed together in preparing the present disk. In nature, carborundum fire sand differs from carborundum in the respect that it is not as hard or as `food an abrasive as carborundum,

which is .probably due to the lower teniperature obtained in the part of the charge in which the fire sand is formed as compared to the temperature obtained in the part where carborundum is formed during the process. However, in the formation, carborundum Acaoss REFERENCE runduplfiresand and is a by-product of tlie 'the process results in a high resistance medium which is not affected by a high temperature, as has been found the .case in other present types of compression resista'nce units. The disks as hereinafter set forth retain their high Contact resistance.

In preparing the resistance disks 6, vthe process is carried out by hand or by machine, the. pieces being sawed'preferably from a cylindrical piece of graphite or hard carbon, thereby forming the disks, and the disks for certain conditions are subjected to the process without being surfaced oil", while disks for other conditions are surfaced off smooth by grinding. To produce the best surface upon the disks they are rubbed witha mixture of carborundum, either crystalline or amorphous or both, although corundum or equivalent materials can be used, combined with an adhesive compound preferably silicate of soda. This is done in'one way by first coating the disks with silicate of soda or water glass, and then placmg'the grains or-p-om carborundum or other material upon the film and mixing and rubbing the same in contact with the surfaces of the disks until a desired smooth surface is effected. The excessive mixture is then removed and the disks are permitted to thoroughly dry before being placed in the tube 5. 100

It is evident, therefore. that the contact surfaces of the various disks may be varied according to the amount of the mixture retained by the surface, the number of times the disks are subjected to the process, and 105 the condition of the surfaces of the disks before beingsubjected to the process.

In order to provide a cooling or radiating means for the resistance unit, two disks 23 and 2l which are {ianged are'placed upon 110 and about the 'tube 4 and have connected therebetween the corrugated cylinder Q5 which is perforated, as at 26, to permit the proper circulation of air therethrough.

It will thus be seen that by positioning the 115 corrugated member 25 about the unit, a proper circulation of air is afforded to properly maintain the unit against overheating, the heat being radiated therefrom through the apertures 26 so that the draft is camara f unit having a plurality of conductor disks unithaving a plurality of conductor members Whose surfaces are coated with a mixture of carborundum having crystalline properties, and an adhesive compound.

3. An electrical compression resistance unit having a plurality of conductor members whose surfaces are coated with a mixture of crystalline and amorphous carborundum combined with an adhesive compound. p

4. An electrical compression resistance whose surfaces are coated with a mixture of crystalline and amorphous carborundum, combined With silicate of'soda.

5.' An electrical compression resistance unit having a plurality of conductor members Whose surfaces are coated with a mix` ture of crystalline carborundum, andv an adhesive compound.

6. An electrical` compression resistance unit having a plurality-.of conductor disks whose surfaces are coated with a mixture of crystalline carborundum and silicate of soda.

7. An electrical compression resistance unit havinga. plurality of conductor members whose surfaces are coated With a mixture of crystalline carborundum and another form of carborundum, combined with an adhesive compound.

8. An electrical compression resistance unit having a plurality of conductor members Whose surfaces are coated with a mixbers Whose surfaces are coated with a mixture of diierent forms of carborundum combined With an adhesive compound.

10. An electrical compression resistance unit having a plurality of conductor disks Whose surfaces are coated with a mixture of crystalline carborundum and another form of carborundum combined with silicate ofsoda.

"`\" 11T-A11 electrical compression resistance unit having a plurality of conductor disks Whose surfaces are coated with a mixture of amorphous carborundum and another form of carborundum combined with silicate of soda.

l2. An electrical compression resistance unit having a plurality of conductor disks Whose surfaces are coated with a mixture of different forms of carborundum combined with silicate of soda.

In testimony that I claim the foregoing asv my own, I have hereto ailixed my signature in the presence of two Witnesses.

PAUL J. RAY.

l/Vitnesses:

LILLIAN RYAN, vKATHRYN RAY. 

